cylonlover writes: The second hypersonic test flight of Boeing's X-51A Waverider has ended prematurely with the craft failing to transition to full power. The X-51A Waverider broke the record for the longest ever supersonic combustion scramjet-powered flight on its first autonomous flight in May 2010, flying under scramjet power for just under three and a half minutes at a top speed of Mach 5. For the second hypersonic flight test, the craft was expected to accelerate to about Mach 6, but only managed to accelerate to Mach 5 before the flight had to be terminated after 143 seconds under scramjet power.